1. Field of the Invention
The present invention relates to a location information system and, more particularly, to a user equipment (UE), system and method for providing a location information service through interworking between a mobile communication system and a wireless local area network (WLAN).
2. Description of the Related Art
In general, a mobile communication system has a function part for calculating a location of a terminal in a mobile communication network to provide a location service and for transferring the calculated location of the terminal to a certain entity periodically or according to a corresponding request.
A network structure related to the location service differs depending on an internal network structure such as a 3GPP network, a 3GPP2 network, etc. Currently, there are several methods for calculating the position (location) of the mobile terminal, including a cell-ID method for transferring an ID of a cell to which a mobile terminal belongs, a method for calculating a location of a mobile terminal through triangulation by measuring the time required for radio waves to reach each base station from the mobile terminal, and a method of using a GPS (Global Positioning System).
In order to provide the location service to a user, a large amount of signaling and position information is transferred between a mobile terminal and a location server. Recently, positioning technologies for providing a location service, namely, the location service provided based on the location of a mobile terminal, are increasingly used. These technologies can be provided generally through a user plane and a control plane, one of which is a SUPL (Secure User Plane Location) technique that provides the location service through the user plane.
Effective for transferring information required for calculating the location of the mobile terminal, the SUPL (Secure User Plane Location) technique uses a user plane data bearer to carry a positioning technology-related protocol between the mobile terminal and a SUPL network.
Generally, in the location information system, the SUPL network related to the location service includes a SUPL agent, an SLP (SUPL location platform) and a SET (SUPL Enabled Terminal), etc. The SUPL agent is a service logical access point (AP) using actually measured location information, and the SLP is a SUPL service AP of a network part that accesses network resources to obtain the location information. The SET is a device for communicating with the SUPL network using a SUPL interface, and can be, for example, one of a UE (User Equipment) of a UMTS, an MS (Mobile Station) of a GSM, an MS of an IS-95, and a laptop computer or a PDA (Personal Digital Assistant) having the SET function.
A network to which the user originally registered is called a home network, and a network of an area to which the user is located after having moved from the home network is called a visited network. An SLP within the home network is called a home SLP (H-SLP), and an SLP within the visited network is called a visited network (V-SLP). When the network starts the SUPL procedure, an SLP first connected by an external client is called a requesting SLP (R-SLP), which is a logical entity that may or may not be the same as the H-SLP. A SET aimed for tracking its current location is called a target SET.
The SLP, a network element, includes an SPC (SUPL Positioning Center) that calculates the actual location information (location/position) of the target SET, and an SLC (SUPL Location Center) that handles additional functions other than calculating the location information. For example, the SLC performs and/or supports the procedures for roaming, resource management, and the like. The SET can calculate the location information through communication with the SPC via the SLC (in case of a proxy mode) or can calculate the location information by directly opening a connection with the SPC (in case of a non-proxy mode).
FIG. 1 is a signal flow chart illustrating a SUPL procedure of a SUPL-based location information system when a network requests location information regarding a particular terminal in a proxy mode and when roaming is not performed.
As shown in FIG. 1, the SUPL-based location information system includes a SUPL agent 1, an SLP 3 and a target SET 5. The SLP 3 is a location server and the target SET 5 is a target terminal.
When the SUPL agent 1 transmits an MLP (Mobile Location Protocol) SLIR (Standard Location Immediate Request) message to the SLP 3 to request location information regarding the target SET 5 (step S11), the SLP 3 checks whether or not the target SET 5 has been roaming, namely, whether or not the target SET 5 currently belongs to a different visited network, and also checks whether or not the target SET 5 supports the SUPL (step S12).
The SLP 3 transmits a SUPL initialization message (SUPL INIT) to the target SET 5 to start the SUPL procedure with the target SET 5 (step S13). In this case, the SUPL initialization message includes at least a session ID, an address of the SLP, and a position method to be used, etc. In addition, privacy, which can be used in a case where a notification related to the location information of the target SET is required to be provided to the user after confirming privacy of the target SET 5 by the SLP 3, can be also included in the SUPL initialization message. Also, an SLP mode indicator (SLP mode), which indicates a mode (e.g., proxy mode, non-proxy mode, etc.) of the SLP 3, can be included in the SUPL initialization message, which is an inventive concept owned by the assignee of the present application and included in a co-pending U.S. patent application.
If the target SET 5, which has received the SUPL initialization message, is not opened for a data connection with any network, it requests a data connection from a packet data network such as a 3GPP or a 3GPP2, etc.
When the data connection is made (step S14), the target SET 5 transmits a SUPL location initialization message (SUPL POS INIT) to the SLP 3 to start a procedure for determining the position/location information of the target SET 5 (step S15). And then, the target SET 5 and the SLP 3 exchange successive messages for performing the actual positioning determining process, and the SLP 3 or the target SET 5 calculates the current location of the target SET 5 through the successive messages (step S16). In this case, the SUPL location initialization (SUPL POS INIT) message includes at least a session ID, an LID (location Identifier) indicating a base station ID, and capabilities of the target SET. The messages exchanged between the target SET 5 and the SLP 3 may include a session ID, a protocol (e.g., an RRLP, an RRC or a TIA-801) to be used for positioning, etc.
After the location of the target SET 5 is calculated, the SLP 3 transmits a SUPL end message (SUPL END) for informing about the termination of the SUPL procedure to the target SET 5 (step S17) and also transmits the calculated location information (posresult) of the target SET 5 to the SUPL agent 1 through an MLP SLIA (Standard Location Immediate Answer) message (step S18).
Recently, as Internet services using the WLAN become more common, interest in a technology that allows a user of a WLAN terminal to be connected with the WLAN through a mobile communication network to receive an Internet service in an area where the WLAN is not supported, exists. A network for applying this technology can be dubbed an I-WLAN (Interworking-WLAN) in the 3GPP, and it would be desirable for the 3GPP network (or other mobile communication network) to provide various supplementary services including the location information service by interoperability (interworking) with the WLAN.
However, because there is neither the network structure nor protocol for providing a location information service (e.g., SUPL service) in the related art system involving the conventional WLAN and 3GPP network, the WLAN terminal cannot receive the location information service through the 3GPP network according to the related art.